Electric furnace.



No: asmss. PATENTED JAN. 1, 1907. w. H, BRISTOL;

E LEOIRIO FURNACE. APPLICATION FILED AUG. s, 1000;

Fig-1- 352 411! C1 l'l'ozucq avoid cracking of crucible or lining.

- WILLIAM H. BRISTOL, NEW YORK, N. Y.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented Jan. 1, 1907.

Application filed August 6,1906. Serial No. 329.334.

To all whom it may concern:

Be it known that 1, WILLIAM H. BRrsToL, a citizen of the United States,and a resident of New York, in the county of New York and State of NewYork, have invented certain heated by means of the electricity passingthrough a heating-coil of suitable resistancewire. I

It has for its object a furnace which may be quickly brought to fullheat; also, a furnace into which the articles may be placed Withoutdanger of short-circuiting or conterminating the heating-coil.

For this purpose my invention consists, essentially, of an electricfurnace comprising a fused-quartz gsilica) receptacle forming aheating-chamber, an electric heating-coil about said receptacle, and arefractory nonconducting material or materials incasing said coil andchamber.

The nature of my invention will best be understood in connection withthe accom panying drawings, in which Figure 1 is a vertical section of acrucible form of furnace. Fig. 2 is a transverse section of a tubularform of furnace.

Similar characters of reference designate corresponding parts throughoutboth views.

The present furnaces of this character utilize some refractory lining orcrucible of magnesia or clay as a heatirig-chamber, into which thearticles or materials to be treated are placed. Urucibles or chambers soformed are provided with starting resistances and considerable time(some ten to fifteen minutes) is required to bring the furnace up to afull heat. This is necessary to especially with the lincdheating-chambers, the articles or materials to be heated freuentlypermeate said lining or crucible and s ort-circuit or attack theheating-coil, causing it to break down.

In my improved furnace ldprovide a heating-chamber formed of fuse quartz(silica) in the shape of a crucible 11), Fig. 1, or a tube, Fig. 2, orof any form suited to the use to which the furnace is to be put. Aboutthis chamber is a heating-wirc 11, preferably of platinum, in the formof a coil and of suitable size to produce the required heat and of suchAlSO,

resistance as to permit of its being directly placed across apredetermined difference of potential. T he successive turns of the coilare by preference insulated from each other by an asbestos cord 12,wound on together and parallel with the platinum wire, Fig. .2.

For the purpose of permitting a consider able amount of resistance-wireto be wound upon the quartz receptacle within a contracted space and inorder to allow of the passage of suilicient current to produce thequantity of heat demanded 1 may make the said wire of flattened form andwind it edgewise with respect to said receptacle, as shown in Fig. 1.Bjy this means I am enabled to wind on 'wire of sufficient cross-sectionto carry the required current.

The quartz crucible or tube, with its sur' rounding coil, is preferablycovered with asbestos 13 and the whole then incased in some refractoryinsulating material 141, as fire-clay, magnesia, &c., to preventradiation. A suitquired The articles or materials to be heated areplaced within the heating-chamber 16 and the full current sent throughcoil 11. he chamber 16 heats very rapidly, coming to a full heat inabout one minute and a half. Owing to the peculiar property of thequartz, the crucible or lining does not craclr under the sudden changesof temperature, and the heat may be quickly turned on or oii withoutdanger of cracking the quartz receptacle. The quartz also acts as afirst-class insulator, and there is no danger of the articles or ma"terials short-circuiting the heating-coil 11 or of penetrating thereceptacle to contaminate said coil. Of course substances which combinewith the silica at the high temperatures employed must not be placed indirect contact with the walls of the heating-chamber.

What I claim as new, and desire to secure by Letters Patent of theUnited States, 18-

1. An electric furnace comprising: a fusedquartz receptacle forming aheating-chamher; an electric heating-coil surrounding the same; and arefractory, non-conducting material incasing said coil and chamber.

' 2. An electricfurnace comprisin": afueedquartz receptacle forming aheatingchamher; a platinum electric heating-coil surrounding the same;and a refractory, nonconducting covering surrounding said coil andchamber.

3. An electric furnace comprising: a fusedable refractory cover 15 isprovided when re quartz receptacle forming a heating-chaml tacle andcoil; and a refractory, non-con luctber; a'platinum electricheating-coil wound upon the same having its successive turns separatedfrom each other by an asbestos cord; and a refractory, non-conductingcoveriug surrounding said coil andc'hamber.

4; An electric furnace comprising: a fusedquartz receptacle forming aheating-chan1- her; acoll or flattened Wire placed edgewise with res ectto the quartz receptacle and surineun the same; and a refractory, non--conducting covering surrounding said coil and chamber. 1

h 5. An electric furnace comprising: alusedquartz receptacle forming aheating-chamber; an electric heating-coil surrounding the same; anasbestos covering aboutsaid receping material incasing the same 6. Anelectric furnace comprising: a fusedquartz receptacle forming aheating-chamuer; an electric heating-coil surrounding the same, havingits successive turns separated from each other by asbestos; an asbestoscovering-about said receptacle and coil; and i arefractory,non-conducting material incasing the same.

York and State of New York, this 4th day of August, A. D. 1906.

WILLIAM H. BRISTOL. Witnesses: EREDK. F. S,GI;IUETZ,

SALLY O. YUDIZKY.

Signed at New York, in the county of New I

